JP4859213B2 - Element base of recording head, recording head, recording apparatus - Google Patents

Description

The present invention includes an element substrate suitable recording head using the ink jet recording apparatus, a recording head, about the recording equipment. More specifically, a plurality of recording elements arranged in a predetermined direction and divided into a plurality of groups by a predetermined number and a drive circuit for driving each recording element are on the same element substrate. element substrate of the recording head provided in the recording head, about the recording equipment.

  For example, as an information output device in a word processor, personal computer, facsimile, or the like, a recording device that records information such as desired characters and images on a sheet-like recording medium such as paper or film is known. In such a recording apparatus, a serial recording system that performs recording while performing reciprocal scanning in a direction perpendicular to the feeding direction of a recording medium such as paper is generally widely used from the viewpoint of being inexpensive and easily miniaturized. .

  The configuration of a recording head used in a recording apparatus that employs such a serial recording method will be described with reference to an example of a recording head that conforms to an ink jet recording method in which recording is performed using thermal energy. An ink jet recording head is provided with a heating element (heater) at a portion communicating with an ejection port (nozzle) that ejects ink droplets as a recording element, and an electric current is applied to the heating element to generate heat and foam the ink to generate ink droplets. Discharge and record. In such a recording head, it is easy to arrange a large number of discharge ports and heating elements (heaters) at a high density, whereby a high-definition recorded image can be obtained.

  A heating element (heater) of a recording head according to a conventional ink jet recording system and a driving circuit thereof are formed on the same element substrate using a semiconductor process technology (Patent Document 1).

  FIG. 1 shows an example of a circuit block layout of an element substrate 100 for a recording head in which a heater and a drive circuit are integrally formed. FIG. 4 is a block diagram schematically showing a circuit provided on one side of the ink supply port on the element substrate 100, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

  In FIG. 1, an elongated hole-shaped ink supply port 101 provided along the long side direction (vertical direction in the drawing) of the element substrate is provided in the approximate center of the element substrate 100. On both sides of the ink supply port 101, an array-like heater array 102, a driver transistor 103 for driving the heater, a booster circuit 105, a logic circuit 104, a data line and a decoder line 111 are arranged symmetrically from the center toward the outside. Has been placed.

  Also, pads 109 for supplying power and electric signals from the outside are provided along the short side direction of the element substrate at both upper and lower ends of the element substrate 100. Further, a circuit including a shift register 106 and a latch 108 is disposed along the inside of the pad 109. A decoder 107 is arranged on one side inside the shift register and latch circuits 106 and 108. Further, a voltage conversion circuit 110 that supplies power to the booster circuit 105 is arranged to extend in the short side direction of the element substrate 100 between the decoder 107 and the portion where the logic circuit 104 is arranged from the ink supply port 101. Yes.

  In the layout shown in FIG. 1, pads 109 corresponding to the heater array 102, driver transistor 103, booster circuit 105, and logic circuit 104 are arranged on the right side of the ink supply port 100. Further, shift registers and latches 106 and 108, a decoder 107, and a voltage conversion circuit 110 are also arranged on the upper side. Also, pads 109 corresponding to the heater array 102, driver transistor 103, booster circuit 105, and logic circuit 104 on the left side of the ink supply port 101 are disposed on the lower side. Further, shift registers and latch circuits 106 and 108, a decoder 107, and a voltage conversion circuit 110 are also arranged on the lower side.

  The heater array 102 of this conventional example is divided into M groups as shown in FIG. Each signal input to the circuit of FIG. 4 is input at a timing as shown in FIG. The data signal DATA synchronized with the clock signal CLK is serially input to the shift register 106 in the order of M-bit data specifying a group and X-bit data specifying a heater in the group. When the data signal DATA of a predetermined bit is input, data is held in the latch circuit 108 at the timing when the latch signal LT changes to low level. Of the data signal DATA input to the shift register 108, the latter half X-bit data is decoded by the decoder 107 into N-bit (X <N) data. With such a circuit configuration using a decoder, the amount of data can be reduced by reducing the amount of data, and the heater can be driven at a higher speed.

  These M-bit and N-bit signals select the driver transistor 103 to be controlled by the M × N matrix drive of the logic circuit 104. The logic circuit 104 further outputs a signal that drives the selected driver transistor 103 for a time (pulse width) defined by a period during which the heat signal HE is at a low level. However, the driver transistor 103 cannot be controlled by the output voltage of the logic circuit 104. Therefore, the booster circuit 105 boosts the voltage to a predetermined voltage and drives the driver transistor 103 to energize and drive the heater array 102. The driver transistor 103 and the heater array 102, in which N is a group, are driven in a time division manner. The number of driver transistors 103 and heater arrays 102 that are driven simultaneously is one per group, and the maximum is M in total. That is, by selecting the M driver transistors 103 and the heater array 102 N times in a time-sharing manner, it is possible to drive the heaters of all the heater arrays 102.

  In this conventional example, power supplied from the outside via the pad 109 includes a power supply voltage VDD (around 3 V) for driving the logic circuit 104 and VSS corresponding to the ground voltage GND. Furthermore, there is a heater voltage VH (around 24V) for driving the heaters of the heater array 102, a corresponding ground voltage GND, GNDH, and a power supply VHT having the same voltage value as the heater voltage VH. The power supply VHT is input to the voltage conversion circuit 110 and converted into a conversion voltage VHTM used as a power supply for the driver transistor 103, the logic 104, and the booster circuit 105. The voltage value of the conversion voltage VHTM is a voltage that can drive the driver transistor 103, and is higher than the power supply voltage VDD and lower than the withstand voltage of the elements that constitute the driver transistor 103 and the booster circuit 105. In this conventional example, the voltage value of the conversion voltage VHTM is around 14V. Thus, by providing the voltage conversion circuit 110, the number of power supply lines supplied from the outside can be minimized, and the cost can be reduced.

  FIG. 2 shows a circuit configuration of the voltage conversion circuit 110 of the conventional example. As shown in the figure, the voltage conversion circuit 110 defines a voltage value of the conversion voltage (VHTM) by applying a constant reference voltage to the gate of the MOSFET 201 adopting the source follower form. When a constant voltage is always applied to the gate of the MOSFET 201, fluctuations in the conversion voltage are suppressed even if the current value flowing between the drain and source of the MOSFET 201 changes. Therefore, in order to keep this conversion voltage constant, it is necessary to always apply a constant voltage to the gate of the MOSFET 201.

For this reason, in the reference voltage generation unit 202 of this example, a constant reference voltage is generated by a voltage dividing resistor. In this case, it is desirable to use, as the resistance element, an element (for example, Poly-Si: polysilicon) that does not easily change in resistance value due to fluctuations in heat or applied voltage. On the other hand, since the source load resistor 203 is not a part that affects the voltage fluctuation of the conversion voltage VHTM as much as the reference voltage generator 202, it is desirable to use an element (for example, a diffused resistor) having a small layout area.
JP-A-5-185594

  As described above, the conversion voltage VHTM is applied to the driver transistor 103, the logic circuit 104, and the booster circuit 105. The conversion voltage VHTM is a voltage value generated (converted) internally by the voltage conversion circuit 110. Have. Therefore, it is unstable and easily fluctuates as compared with a power supply supplied from the outside such as the heater voltage VH and the power supply voltage VDD.

  If the converted voltage VHTM becomes unstable, for example, if the converted voltage VHTM drops significantly, the driver transistor 103 cannot be driven. Furthermore, the logic circuit 104 and the booster circuit 105 cannot be driven, which may cause a malfunction. In addition, as apparent from the layout of the element base 100 shown in FIG. 1, the voltage conversion circuit 110 that supplies the conversion voltage VHTM is arranged on one side of the corresponding driver transistor 103, logic circuit 104, and booster circuit 105. Has been. Therefore, the voltage supplied to a circuit separated from the voltage conversion circuit 101 is likely to be lowered or unstable due to the influence of wiring resistance or the like, compared to the voltage supplied to a circuit in the vicinity of the voltage conversion circuit 110.

  On the other hand, in recent years, with the increase in speed and image quality of ink jet recording apparatuses, the shape of the element base of the recording head tends to become longer in order to increase the number of nozzles. As the length increases, the wiring of the conversion voltage VHTM becomes longer, and the above problem becomes more serious. In addition, since the number of elements that are driven simultaneously increases as the speed increases, it is necessary to further stabilize the voltage of the conversion voltage VHTM.

  In order to stabilize the voltage of the conversion voltage VHTM, it is effective to increase the size of the voltage conversion circuit 110. Specifically, the size of the MOSFET 201 is generally increased so that more current can be supplied. However, if it does so, the area of an element base | substrate will become still larger, and will lead to a cost increase.

  SUMMARY OF THE INVENTION In view of the above situation, the present invention aims to supply a stable voltage from a voltage conversion circuit and suppress an increase in the area of the entire element substrate even when the number of recording elements is increased or lengthened. And

In order to achieve the above object, an element substrate of a recording head according to an embodiment of the present invention includes:
A plurality of recording elements arranged along a predetermined direction ;
A plurality of driver transistors provided corresponding to each of the plurality of recording elements, and driving the plurality of recording elements;
Selecting means for outputting a signal for selecting a recording element to be driven among the plurality of recording elements;
A plurality of boosting units arranged along the predetermined direction, and boosting a voltage of a signal output from the selection unit and supplying the boosted voltage to the driver transistor;
A voltage supply means having a reference voltage generating section for generating a reference voltage and a plurality of transistors arranged in each region where the boosting means is arranged and generating a voltage to be supplied to the boosting means based on the reference voltage When
It is characterized by providing .

  According to the present invention, a stable voltage can be supplied from the voltage conversion circuit and an increase in the area of the entire element substrate can be suppressed even when the number of recording elements is increased or lengthened.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the components described in the following embodiments are merely examples, and are not intended to limit the scope of claims of the present invention only to them.

  In this specification, the term “element substrate” does not indicate a simple substrate made of a silicon semiconductor, but indicates a substrate provided with each element, circuit, wiring, and the like. The substrate may be a plate or chip substrate.

  Furthermore, the expression “on the element substrate” not only indicates the element substrate, but also indicates the surface of the element substrate and the inside of the element substrate near the surface. In addition, the term “built-in” as used in the present invention is not a term indicating that each individual element is simply placed on the element substrate, but each element is integrated on the element substrate by a semiconductor circuit manufacturing process or the like. It shows that it is formed and manufactured automatically.

  The voltage conversion circuit in the present embodiment includes a reference voltage generation unit and a voltage conversion unit, and includes a plurality of voltage conversion elements in which the voltage conversion units are arranged in a distributed manner. The reference voltage of the reference voltage generator is a voltage that becomes a reference for the conversion voltage VTHM.

  Also, when the number of recording elements is increased, the area in which voltage conversion elements are arranged increases as the length in the direction in which the recording elements are arranged increases. Therefore, it becomes easy to cope with an increase in the number of recording elements and an increase in length.

  Therefore, even when the number of recording elements is increased or lengthened, a stable voltage can be supplied from the voltage conversion circuit, and an increase in the area of the entire element substrate can be suppressed. The predetermined direction is a longitudinal direction of an elongated hole-shaped ink supply port for supplying ink provided in the element base, and the predetermined direction is in order of the recording element, the driver transistor, and the logic circuit from the ink supply port. It may be arranged along. The reference voltage generation unit may be arranged to extend in a direction intersecting with the predetermined direction.

  One voltage conversion element may be arranged for each group having a predetermined number of adjacent recording elements as a unit. Within the group of the present embodiment, the recording elements are configured not to be driven simultaneously. Between different groups of printing elements, multiple printing elements in the same block can be driven substantially simultaneously. As described above, when one recording element is driven in each group, the voltage conversion element may have a performance corresponding to one recording element, and the size may be small. Further, the voltage conversion elements arranged in each group need only be arranged in each group and can be easily formed. As another example, a configuration in which two to three recording elements are simultaneously driven in the same group can be used. However, since the voltage conversion element is also enlarged correspondingly, one recording element in the same group. It is preferable to have a configuration in which only driving is possible.

  In this case, the booster circuit is provided corresponding to each recording element, and may be arranged along a predetermined direction between the driver transistor and the logic circuit. Alternatively, the logic circuit may include a logic circuit driven with an intermediate voltage, a booster circuit may be provided for each group, and may be disposed outside the logic circuit along the predetermined direction. The plurality of voltage conversion elements are dispersed in a region where any one of the driver transistor, the booster circuit, and the logic circuit is arranged, or in a region where at least two of the driver transistor, the booster circuit, and the logic circuit are arranged. May be arranged.

  As the voltage conversion element, any one of a MOSFET, a bipolar transistor, and a diode can be used, and the reference voltage generation unit may include a resistance element made of polysilicon. Polysilicon has a performance that resistance values hardly change due to changes in heat and applied voltage. As the recording element, an element including a heating element (heater) for applying thermal energy to the ink may be used.

  The present invention also includes a recording head that includes the element base of the recording head described above, ejects ink, a recording apparatus that performs recording using the recording head, and a recording head cartridge that includes the recording head and the ink cartridge. Applicable.

  According to the present invention, the wiring length from each of the distributed voltage conversion elements to the booster circuit is shortened. Therefore, even when the total size of the dispersed voltage conversion elements is equal to the size in the conventional arrangement, the influence of the wiring resistance and the like is reduced, so that a stable intermediate voltage can be supplied.

  Also, when the number of recording elements is increased, the area in which voltage conversion elements are arranged increases as the length in the direction in which the recording elements are arranged increases. Therefore, it becomes easy to cope with an increase in the number of recording elements and an increase in length. Therefore, even when the number of recording elements is increased or lengthened, a stable voltage can be supplied from the voltage conversion circuit, and an increase in the area of the entire element substrate can be suppressed.

  In the following embodiments of the present invention, parts similar to those shown in the above-described conventional example are denoted by the same reference numerals, and detailed description thereof is omitted.

<Embodiment 1>
FIG. 5 is a diagram showing a layout of circuit blocks on the element substrate 100 according to the first embodiment of the present invention. FIG. 6 is a circuit diagram of a block arranged on one side of the ink supply port on the element substrate 100 of FIG.

  Comparing the conventional example described above with reference to FIGS. 1 to 4 and the first embodiment, in the conventional example, the voltage conversion circuit corresponding to the circuit blocks arranged symmetrically on the left and right sides of the ink supply port 101 is used. 110 are arranged below and above the ink supply port 101, respectively. On the other hand, in the first embodiment, the voltage conversion circuit is divided and arranged in the resistance unit 501 and the MOSFET unit 502.

  Specifically, the voltage conversion circuit is divided into a resistance unit 501 composed of a resistive element such as a voltage dividing resistor of the reference voltage generation unit 202 and a source load resistor 203, and the size is divided corresponding to a group of heaters. The area is divided into a MOSFET section 502 having a smaller size. And the resistance part 501 can enlarge an arrangement area. Therefore, it is difficult to divide and arrange, and since there are few merits to arrange in parallel with the heater array 102, the voltage conversion circuit 110 is arranged at the same position as in FIG. On the other hand, the MOSFET section 502 is distributed between the booster circuits 105 for each heater group of the heater array 102.

  The reference voltage generated by the voltage dividing resistor of the reference voltage generation unit 202 is routed to each group of the heater array 102 together with the power supply VHT input from the pad unit 109. Then, the signal is input to the gate and drain of the MOSFET section 502 that is distributed between the booster circuits 105. At this time, the converted voltage VHTM is supplied from the corresponding MOSFET unit 502 disposed between the booster circuits 105 to the booster circuit 105 that generates the drive power for the driver transistor 103.

  Also in the first embodiment, the three voltages of the power supply voltage VDD, the conversion voltage VHTM, and the heater voltage VH have a relationship of VDD <VHTM <VH, and are approximately 3V, 14V, and 24V, respectively. Thus, the conversion voltage VHTM is generated as an intermediate voltage having a potential between the power supply voltage VDD of the logic circuit 104 and the heater voltage VH of the heaters of the heater array 102.

  As described above, the MOSFETs 502 as the supply source of the conversion voltage VHTM of the voltage conversion circuit are distributed in the vicinity of the circuit (boost circuit 105) that actually uses the conversion voltage VHTM. For this reason, even when the total size of the distributed MOSFETs 502 is equal to the size in the conventional arrangement, the influence of wiring resistance and the like is reduced, so that a stable voltage can be supplied with the conversion voltage VHTM.

  The basic circuit configuration of the first embodiment is the same as the conventional configuration as shown in FIG. 2 except for the voltage conversion circuit, and only the arrangement of the voltage conversion circuit needs to be changed. Reduced and easy to implement. In the first embodiment of the present application and the embodiments described below, the voltage conversion circuit operates to convert an input voltage to a lower voltage.

  Furthermore, if the number of nozzles is increased and the element substrate 100 is made longer, the number of circuits driven by the conversion voltage VHTM increases, so that it is necessary to further stabilize the voltage conversion circuit. In the conventional configuration, in order to stabilize the voltage output from the voltage conversion circuit 110, it is necessary to increase the size of the MOSFET. Therefore, it is necessary to increase the layout area of the voltage conversion circuit 110. On the other hand, in the configuration of the first embodiment, the MOSFET of the voltage conversion circuit is arranged corresponding to each group. For this reason, even if the number of nozzles increases and the number of circuits driven by the conversion voltage VHTM increases, the number of groups including MOSFETs can be simply increased.

  In the first embodiment, a MOSFET is used as the voltage conversion element. This is because MOSFETs have various advantages such as being effective for digital circuits, having a smaller area on the element substrate than bipolar transistors and diodes, and being able to cope with downsizing of the substrate, and a simple manufacturing process. It is.

<Embodiment 2>
FIG. 7 shows a layout of a circuit block on the element substrate 100 according to the second embodiment of the present invention. FIG. 8 is a circuit diagram of a block arranged on one side of the ink supply port on the element substrate 100 of FIG.

  In the conventional example and the first embodiment described above, the voltage of the data output from the shift register and whose logic is determined by the logic circuit 104 is reduced to a voltage that can drive the driver transistor 103 by the booster circuit 105 (that is, the conversion voltage VHTM). Configured to boost. On the other hand, in the second embodiment, the voltage of the data signal is boosted before the logic by the logic circuit 104 is determined.

  Specifically, a signal for selecting a group output from the shift register and the latch is boosted to the conversion voltage VHTM by the booster circuit 105. Then, the boosted data signal is used to determine the logic by the logic circuit 104 operating at a high voltage, and the driver transistor 103 is driven using the output as it is. In this way, the number of booster circuits 105, which has conventionally been the same as the number of heaters, can be reduced, and the size of the element substrate can be further reduced.

  The voltage conversion circuit is configured in the same manner as in the first embodiment. That is, a resistance unit 501 composed of a resistive element such as a voltage dividing resistor of the reference voltage generation unit 202 and a source load resistor 203, and a MOSFET unit 502 that is divided in accordance with a group of heaters and has a small size per unit. It is divided into. The resistor unit 501 is disposed at the same position as the voltage conversion circuit 110 in FIG. 1, while the MOSFET unit 502 is distributed between the booster circuits 105 for each heater group. ing.

  In the first embodiment, the conversion voltage VHTM is supplied to the booster circuit 105. However, in the second embodiment, the conversion voltage VHTM is higher than that of the booster circuit 105 as shown in FIG. The voltage is supplied to the logic circuit 104 operating with voltage. Therefore, as shown in FIG. 7, the driver transistor 103, the logic 104, the booster circuit 105, and the MOSFET unit 502 are arranged in this order from the heater array 102 toward the outside of the element substrate 100.

  In the second embodiment, as shown in FIG. 8, the shift register 106, the decoder 107, and the latch 108 are divided into a shift register and latch corresponding to the X bit, the decoder 107, and an M bit shift register and latch. did. The M-bit shift register and the latch are divided in units of 1 bit for each group. For this reason, it arrange | positions as shown in FIG. That is, the shift register 106, the decoder 107, and the latch 108 are parallel to the heater array 102 outside the booster circuit 105 in the long side direction of the element base 100 from the portion where the shift base 106 is aligned with the resistor 501 of the voltage conversion circuit in the short side direction. It is arranged in the part that extends.

  With this arrangement, in the conventional example of FIG. 1 and the first embodiment of FIG. 5, the wiring region 111 of the data lines and decoder lines that occupy a relatively large area on the outer side in the long side direction of the element base 100 is formed. Can be eliminated. Therefore, the size of the element base 100 in the short side direction can be reduced. In addition, since the wiring lengths of the shift register 106, the decoder 107, and the latch 108 can be shortened, a highly reliable circuit with excellent noise resistance can be realized.

  This configuration is also effective when the number of nozzles increases and the number of groups increases. There is no need to change the length of each group in the short side direction, and only the length of the element substrate in the long side direction is increased. It can respond.

<Embodiment 3>
FIG. 9 is a diagram showing a layout of circuit blocks on the element substrate 100 according to the third embodiment of the present invention. FIG. 10 is a circuit diagram of a block arranged on one side of the ink supply port on the element substrate 100 of FIG.

  In the third embodiment, the position of the MOSFET part in the second embodiment is changed. That is, in the second embodiment, the MOSFET unit 502 of the voltage conversion circuit is distributed between the booster circuits 105. On the other hand, in the third embodiment, the driver transistors 103 are arranged in a distributed manner.

  This is because the driver transistor 103 has a large gate capacitance and consumes a larger amount of current than the logic 104 and the booster circuit 105 that operate at a high voltage. Therefore, the conversion voltage VHTM is more stabilized by disposing the MOSFET portion 502 in the vicinity of the driver transistor 103.

  In the third embodiment, as shown in FIGS. 8 and 9, the MOSFET section 502 of the voltage conversion circuit is arranged between the groups of driver transistors 103. More specifically, as shown in FIG. 8, a stable voltage can be supplied to the driver transistor 103 into which a large amount of current flows by disposing the MOSFET portion 502 of the voltage conversion circuit closer to the gate input portion of the driver transistor 103. .

  Also in the third embodiment, the conversion voltage VHTM generated by the MOSFET unit 502 is supplied not only to the booster circuit 105 but also to the logic circuit 104 that drives the driver transistor 103.

  Here, an example in which the MOSFET portion 502 of the voltage conversion circuit is arranged between the driver transistors 103 is shown. However, the same effect can be obtained by disposing the MOSFET portion 502 between the logic circuits 104 that operate at a high voltage disposed in the vicinity of the driver transistor 103.

<Embodiment 4>
FIG. 11 is a diagram showing a layout of a circuit block on the element substrate 100 according to the fourth embodiment of the present invention.

  In the fourth embodiment, a plurality of MOSFET sections of the voltage conversion circuit are provided corresponding to each circuit block to which the conversion voltage VHTM is supplied for each group. That is, in the second and third embodiments, in addition to the circuit block (the logic circuit 104 and the booster circuit 105) to which the conversion voltage VHTM is supplied, the voltage conversion is performed in the vicinity of any one of the three circuit blocks including the driver transistor 103. The MOSFET part of the circuit was placed. However, in the fourth embodiment, as shown in FIG. 11, the MOSFET unit 702 of the voltage conversion circuit is disposed in the vicinity of the three circuit blocks.

  As a result, the conversion voltage VHTM supplied to each circuit block is generated by the MOSFET unit 702 disposed in the vicinity thereof, so that a stable voltage can be supplied to all the circuit blocks driven by the conversion voltage VHTM. It becomes possible. In this case, if the size of each MOSFET is determined in accordance with the power consumption of the corresponding circuit block, the area efficiency is high and a highly stable design is possible.

<Embodiment 5>
In the second to fourth embodiments, the shift register 106, the decoder 107, and the latch 108 are arranged along the heater array 102 outside the booster circuit 105 in the long side direction of the element substrate 100. Also, the voltage conversion circuit VHTM is stably supplied by disposing the MOSFET portion of the voltage conversion circuit in the vicinity of the driver transistor 103, the logic circuit 104, and the booster circuit 105 in the direction along the heater array 102. is there. At the same time, these circuit arrangements have the effect of greatly reducing the layout area of the element substrate 100.

  Therefore, in the fifth embodiment, functional circuits 801 and 1001 are arranged in a substrate end space where a voltage conversion circuit, a shift register, a latch, a decoder and the like as shown in FIG. (FIG. 12) Examples of the function circuits 801 and 1001 to be arranged include the function circuits described in Japanese Patent Laid-Open Nos. 2001-130002 and 2004-181679. Since such a functional circuit is suitable for being arranged near both ends in the longitudinal direction of the element base 100, the area of the portion where the voltage conversion circuit is arranged in the conventional example can be greatly reduced, which is very effective. .

  In addition, when it is necessary to supply the conversion voltage VHTM to the function circuits 801 and 1001, a voltage conversion unit or a MOSFET is also provided in the function circuit. By doing so, the influence of the fluctuation of the converted voltage VHTM in the functional circuit on other circuits can be minimized, which is effective in stabilizing the converted voltage VHTM.

<Modification 1>
In the first to fifth embodiments described above, the MOSFET is used as the voltage conversion element of the voltage conversion circuit. However, a bipolar transistor may be used instead of the MOSFET. In that case, all the MOSFET parts of the above embodiments are replaced with bipolar transistors.

  Moreover, it is good also as a structure which used the diode instead of MOSFET as a voltage conversion element of a voltage conversion circuit. In that case as well, all the MOSFET parts of the above embodiments are replaced with diodes.

<Modification 2>
Further, in the third to fifth embodiments, the configuration and arrangement of the shift register, latch, and decoder are the same as those in the second embodiment. However, even if these are configured and arranged as shown in the conventional example and the first embodiment, the same effect can be obtained by arranging the MOSFET portions of the voltage conversion circuit between or near the driver transistor groups.

<Modification 3>
In the second to fifth embodiments, the M-bit shift register and the latch are divided in units of 1 bit for each group. However, the number of divisions of the M-bit shift register and latch may not be the same as the number of heaters in the group (time division number: N).

  For example, a shift register and a latch circuit may be arranged together between two groups, and the division number of the M-bit shift register and latch may be half of the time division number N.

  The number of divisions of the shift registers and latches is such that the total area of the element substrate is reduced according to the number N of time divisions and the number M of groups, the heater density and the number of heaters, and the layout area ratio of the shift register and the decoder. Is appropriately selected.

<Other embodiments>
The features of Embodiments 1 to 5 and Modifications 1 to 3 described above may be selectively combined depending on the desired number of nozzles, circuit configuration, desired characteristics, and the like.

  For example, FIG. 13 shows an example in which the source load of the voltage conversion circuit in FIG. 2 is distributed and arranged for each group in the same manner as the voltage conversion unit. The source load is for using the VHTM voltage in a stable region by suppressing the current flowing between the source of the MOSFET and GND and flowing from the source. Even when the voltage converter is composed of a bipolar transistor or a diode, the same effect can be obtained by attaching a load between the transistor and GND.

  In another embodiment, a plurality of resistance portions 203 are provided as source loads, and the resistance portions 203 serving as source loads are distributed and arranged for each group of recording elements. By adopting such an embodiment, when viewed in units of all groups, even if the number of printing elements that are driven simultaneously fluctuates, it is possible to achieve a circuit configuration that is less susceptible to voltage drop. In addition, voltage rounding caused by the length of the wiring can be suppressed, and a stable voltage conversion circuit is obtained.

  As described above, a so-called bubble jet (registered trademark) ink jet recording in which ink is rapidly heated and vaporized using a heating element (heater) as a recording element, and ink droplets are ejected from the orifice by the pressure of the generated bubbles. The head has been described as an example. However, it will be apparent that the present invention can be applied to a recording head that performs recording by other methods as long as it has a recording element array composed of a plurality of recording elements. In this case, instead of the heater in each of the above embodiments, a recording element used in each method is provided.

  In the above embodiment, among the ink jet recording methods, those provided with means (for example, an electrothermal converter) for generating thermal energy as energy used for ink ejection are used. As described above, by using a method in which a change in the state of ink is caused by thermal energy, it is possible to achieve higher recording density and higher definition.

  The present invention is not limited to the recording head and the element substrate of the recording head shown in the above embodiment, but also a recording head cartridge having such a recording head and an ink container for holding ink to be supplied to the recording head. Applicable. Furthermore, the present invention can also be applied to a system that includes the above-described recording head and includes a control unit that supplies recording data to the recording head. These systems include, for example, printers, copiers, facsimile machines, and the like, and also include a plurality of devices including such devices, such as host computers, interface devices, readers, printers, and the like.

  Hereinafter, a recording apparatus having the above-described recording head, a mechanical configuration of the recording head, and an example of a recording head cartridge will be described with reference to the drawings.

<Description of inkjet recording apparatus>
FIG. 14 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus that performs recording by the recording head according to the present invention.

  As shown in FIG. 14, an ink jet recording apparatus (hereinafter referred to as a recording apparatus) includes a carriage 2 equipped with a recording head 3 that performs recording by discharging ink according to an ink jet system. Here, the driving force generated by the carriage motor M1 is transmitted from the transmission mechanism 4, and the carriage 2 is reciprocated in the arrow A direction. Further, for example, the recording medium P such as recording paper is fed through the paper feeding mechanism 5 and conveyed to the recording position, and recording is performed by ejecting ink from the recording head 3 to the recording medium P at the recording position. .

  Further, in order to maintain the state of the recording head 3 satisfactorily, the carriage 2 is moved to the position of the recovery device 10 and the ejection recovery process of the recording head 3 is intermittently performed.

  In addition to mounting the recording head 3 on the carriage 2 of the recording apparatus, an ink cartridge 6 for storing ink to be supplied to the recording head 3 is mounted. The ink cartridge 6 is detachable from the carriage 2.

  The recording apparatus shown in FIG. 14 can perform color recording. For this purpose, the carriage 2 is equipped with four ink cartridges containing magenta (M), cyan (C), yellow (Y), and black (K) inks, respectively. These four ink cartridges are detachable independently.

  Now, the carriage 2 and the recording head 3 can achieve and maintain a required electrical connection by properly contacting the joint surfaces of both members. The recording head 3 applies energy according to a recording signal to selectively eject ink from a plurality of ejection ports for recording. In particular, the recording head 3 of this embodiment employs an ink jet recording system that ejects ink using thermal energy. Accordingly, an electrothermal converter is provided to generate thermal energy, and the electric energy applied to the electrothermal converter is converted into thermal energy. Then, the ink is ejected from the ejection port using the pressure change caused by the growth and contraction of the bubble after the bubble is generated by the film boiling caused by applying the thermal energy to the ink. The electrothermal transducer is provided corresponding to each of the ejection ports, and ink is ejected from the corresponding ejection port by applying a pulse voltage to the corresponding electrothermal transducer in accordance with the recording signal.

  As shown in FIG. 14, the carriage 2 is connected to a part of the drive belt 7 of the transmission mechanism 4 that transmits the driving force of the carriage motor M <b> 1, and slides in the direction of arrow A along the guide shaft 13. Freely guided and supported. Accordingly, the carriage 2 reciprocates along the guide shaft 13 by forward and reverse rotations of the carriage motor M1. A scale 8 is provided for indicating the absolute position of the carriage 2 along the direction of movement of the carriage 2 (the direction of arrow A). In this embodiment, the scale 8 uses a transparent PET film with black bars printed at a necessary pitch, one of which is fixed to the chassis 9 and the other is supported by a leaf spring (not shown). Yes.

  Further, the recording apparatus is provided with a platen (not shown) facing the discharge port surface where the discharge port (not shown) of the recording head 3 is formed. Then, the carriage 2 on which the recording head 3 is mounted is reciprocated by the driving force of the carriage motor M1, and at the same time, a recording signal is given to the recording head 3 to eject ink, thereby conveying the recording medium P conveyed onto the platen. Recording is performed over the full width.

  Further, in FIG. 14, reference numeral 14 denotes a transport roller that is driven by a transport motor M <b> 2 to transport the recording medium P. Reference numeral 15 denotes a pinch roller that abuts the recording medium P against the conveying roller 14 by a spring (not shown), 16 denotes a pinch roller holder that rotatably supports the pinch roller 15, and 17 denotes a conveying that is fixed to one end of the conveying roller 14. It is a roller gear. Then, the transport roller 14 is driven by the rotation of the transport motor M2 transmitted to the transport roller gear 17 through an intermediate gear (not shown).

  Further, reference numeral 20 denotes a discharge roller for discharging the recording medium P on which an image is formed by the recording head 3 to the outside of the recording apparatus, and is driven by transmitting the rotation of the transport motor M2. . The discharge roller 20 abuts on a spur roller (not shown) that presses the recording medium P by a spring (not shown). Reference numeral 22 denotes a spur holder that rotatably supports the spur roller.

  Furthermore, in the recording apparatus, as shown in FIG. 14, the recording head 3 is placed at a desired position outside the range of reciprocating motion (outside the recording area) for the recording operation of the carriage 2 on which the recording head 3 is mounted. A recovery device 10 is provided for recovering the ejection failure. This desired position is called a home position.

  The recovery device 10 includes a capping mechanism 11 for capping the ejection port surface of the recording head 3 and a wiping mechanism 12 for cleaning the ejection port surface of the recording head 3. In conjunction with the capping of the ejection port surface by the capping mechanism 11, ink is forcibly discharged from the ejection port by a suction means (a suction pump or the like) in the recovery device 10. As a result, a discharge recovery process such as removing ink or bubbles with increased viscosity in the ink flow path of the recording head 3 is performed.

  Further, when the recording head 3 is not in operation or the like, the ejection port surface of the recording head 3 is capped by the capping mechanism 11 to protect the recording head 3 and to prevent ink evaporation and drying. On the other hand, the wiping mechanism 12 is disposed in the vicinity of the capping mechanism 11 and wipes ink droplets adhering to the ejection port surface of the recording head 3.

  The capping mechanism 11 and the wiping mechanism 12 can keep the ink ejection state of the recording head 3 normal.

<Control configuration of inkjet recording apparatus>
FIG. 15 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 15, the controller 900 includes an MPU 901, a program corresponding to a control sequence to be described later, a required table, a ROM 902 that stores other fixed data, and the like. Also, a special-purpose integrated circuit (ASIC) 903 that generates control signals for controlling the carriage motor M1, the conveyance motor M2, and the recording head 3, a recording data development area, and a program execution work A RAM 904 provided with a use area and the like is provided. Furthermore, a system bus 905 is provided that connects the MPU 901, the ASIC 903, and the RAM 904 to each other to exchange data. Furthermore, an analog signal from a sensor group described below is input and A / D converted, and an A / D converter 906 that supplies a digital signal to the MPU 901 is provided.

  In FIG. 15, reference numeral 910 denotes a computer (or an image reading reader, digital camera, or the like) serving as a recording data supply source, and is collectively referred to as a host device. Recording data, commands, status signals, and the like are transmitted and received between the host device 910 and the recording device via an interface (I / F) 911.

  Reference numeral 920 denotes a switch group, which instructs to start a power switch 921, a print switch 922 for instructing the start of printing, and a process (recovery process) for maintaining the ink ejection performance of the recording head 3 in a good state. A recovery switch 923 and the like. These are configured as switches for receiving command inputs from the operator. Reference numeral 930 denotes a position sensor 931 such as a photocoupler for detecting the home position h, a temperature sensor 932 provided at an appropriate location of the recording apparatus for detecting the environmental temperature, and the like. It is a sensor group.

  Further, 940 is a carriage motor driver that drives a carriage motor M1 for reciprocating scanning of the carriage 2 in the direction of arrow A, and 942 is a conveyance motor driver that drives a conveyance motor M2 for conveying the recording medium P.

  The ASIC 903 transfers drive data (DATA) of the printing element (ejection heater) to the printing head 3 while directly accessing the storage area of the RAM 902 during printing scanning by the printing head 3.

<Configuration of recording head>
FIG. 16 is an exploded perspective view showing the mechanical configuration of the recording head 3 used in the recording apparatus described above.

  Reference numeral 1101 shown in FIG. 16B denotes an element substrate in which a circuit configuration described later is integrally formed on a substrate such as silicon. On the element base 1101, a heating resistor 1112 as an electrothermal conversion element constituting a recording element is formed, and a flow path 1111 is formed surrounding the resistor 1112 toward both sides of the substrate. As a member constituting the flow path, a resin such as a dry film, SiN, or the like can be used.

  The orifice plate 1102 shown in FIG. 16A has a plurality of discharge ports 1121 corresponding to positions facing the heating resistor 1112 and is joined to a member constituting the flow path.

  Further, a wall member 1103 in FIG. 16C is for constituting a common liquid chamber for supplying ink, and an end portion of the element substrate 1101 from the common liquid chamber to each flow path. Ink is supplied so as to go around.

  Note that connection terminals 1113 for receiving data and signals from the recording apparatus main body are provided on both sides of the element base 1101.

<Recording head cartridge>
The present invention can also be applied to a printhead cartridge having the printhead described above and an ink tank for holding ink supplied to the printhead. As a form of such a recording head cartridge, either a structure integral with the ink tank or a structure separable from the ink tank may be used.

  FIG. 17 is an external perspective view showing a configuration of a recording head cartridge IJC in which an ink tank and a recording head are integrally configured. Inside the head cartridge IJC, the ink tank IT and the recording head IJH are separated at the position of the boundary line K shown in FIG. 17, but they cannot be individually replaced. When the head cartridge IJC is mounted on the carriage HC, an electrode (not shown) for receiving an electrical signal supplied from the carriage HC side is provided. The electrical signal drives the recording head IJH as described above to eject ink.

  The head cartridge may be configured by filling or refilling ink in the ink tank.

  In FIG. 17, reference numeral 500 denotes an ink discharge port array, which has a black nozzle array and a color nozzle array. The ink tank IT is provided with a fibrous or porous ink absorber to hold ink.

  FIG. 18 is an external perspective view showing the configuration of a recording head cartridge in which the ink tank and the recording head are separable. The recording head cartridge H1000 includes an ink tank H1900 that stores ink, and a recording head H1001 that discharges ink supplied from the ink tank H1900 from nozzles according to recording information. Therefore, a so-called cartridge system that is detachably mounted on the carriage is adopted.

  The recording head cartridge H1000 shown here enables photographic-like color recording with high image quality. Therefore, as ink tanks, for example, black, light cyan, light magenta, cyan, magenta, and yellow ink tanks for each color are prepared. As shown in the figure, each is detachable from the recording head H1001.

It is a figure which shows an example of the circuit block layout of the conventional element base | substrate. It is a circuit diagram of a voltage conversion circuit. It is a timing chart of each signal inputted into an element base. It is a block diagram which shows roughly the circuit provided in the element base | substrate of FIG. It is a figure which shows the circuit block layout of the element base | substrate by Embodiment 1 of this invention. FIG. 6 is a block diagram schematically showing a circuit provided on the element substrate of FIG. 5. It is a figure which shows the circuit block layout of the element base | substrate by Embodiment 2 of this invention. It is a block diagram which shows roughly the circuit provided in the element base | substrate of FIG. It is a figure which shows the circuit block layout of the element base | substrate by Embodiment 3 of this invention. FIG. 10 is a block diagram schematically showing a circuit provided on the element substrate of FIG. 9. It is a figure which shows the circuit block layout of the element base | substrate by Embodiment 4 of this invention. It is a figure which shows the circuit block layout of the element base | substrate by Embodiment 5 of this invention. FIG. 6 is a block diagram schematically showing a circuit in which source loads are distributed according to another embodiment of the present invention. 1 is an external perspective view illustrating an outline of a configuration of an ink jet recording apparatus that performs recording by a recording head to which an embodiment of the present invention is applied. It is a block diagram which shows the control structure of the recording device to which other embodiment of this invention was applied. It is a disassembled perspective view which shows the mechanical structure of the inkjet recording head to which other embodiment of this invention was applied. FIG. 6 is an external perspective view showing a configuration of a recording head cartridge according to another embodiment of the present invention in which an ink tank and a recording head are integrally formed. FIG. 7 is an external perspective view showing a configuration of a recording head cartridge according to another embodiment of the present invention in which an ink tank and a recording head are configured to be separable.

Claims (16)

A plurality of recording elements arranged along a predetermined direction ;
A plurality of driver transistors provided corresponding to each of the plurality of recording elements, and driving the plurality of recording elements;
Selecting means for outputting a signal for selecting a recording element to be driven among the plurality of recording elements;
A plurality of boosting units arranged along the predetermined direction, and boosting a voltage of a signal output from the selection unit and supplying the boosted voltage to the driver transistor;
A voltage supply means having a reference voltage generating section for generating a reference voltage and a plurality of transistors arranged in each region where the boosting means is arranged and generating a voltage to be supplied to the boosting means based on the reference voltage When
Element substrate of the recording head, characterized in that it comprises a. 2. The recording according to claim 1, wherein the transistor generates an intermediate voltage having a potential between a driving voltage of the recording element and a power supply voltage of the selection unit as a power supply voltage of the boosting unit. Element base of the head. The predetermined direction corresponds to the longitudinal direction of an elongated hole-shaped ink supply port provided in the element base for supplying ink,
The said element substrate, the claims from the ink supply port, the recording device, configuration thereof along a direction intersecting the predetermined direction in the order of said driver transistor and said selection means is arranged, it is characterized by 3. An element substrate of the recording head according to 1 or 2. Said plurality of recording elements, for each group in units of number of predetermined adjacent said transistors are arranged, elements of the recording head according to any one of claims 1 to 3, characterized in that Substrate. Said boosting means, said plurality of et provided corresponding are to each recording element of the recording element, the element substrate of the recording head according to any one of claims 1 to 4, characterized in that. Before SL boosting means, said plurality of recording elements provided for each group in units of number of predetermined adjacent recording head according to any one of claims 1 to 4, characterized in that Element substrate. 7. The print head element substrate according to claim 1, wherein the selection unit includes a decoder, a shift register, and a latch. The transistor, MOSFET and comprises a bipolar transistor, element substrate of the recording head according to any one of claims 1 to 7, characterized in that. The reference voltage generating unit includes a resistive element, the element substrate of the recording head according to any one of claims 1 to 8, characterized in that. The recording head element base according to claim 9 , wherein the resistance element is made of polysilicon. It said voltage supply means, a load is connected between ground and said plurality of transistors, elements substrate of the recording head according to any one of claims 1 to 10, characterized in that. Said voltage supplying means includes a plurality of loads, the load, the are arranged a plurality of number of predetermined adjacent printing elements in each group in units, it in claim 11, wherein An element substrate of the recording head. The load element substrate of the recording head according to claim 11 or 12 comprising a resistive element, characterized in that. The recording element includes a heating element for applying thermal energy to the ink, the element substrate of the recording head according to any one of claims 1 to 13, characterized in that. A recording head element substrate according to any one of claims 1 to 14 ,
A recording head, characterized in that an ejection port for ejecting ink is provided corresponding to each of the recording elements. A recording heads of claim 15, the recording apparatus characterized by.

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